#include"mystdio.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

MyFile *BuyFile(int fd,int flag)
{
    MyFile *f=(MyFile*)malloc(sizeof(MyFile));
    if(f==NULL) return NULL;
    f->bufferlen=0;
    f->fileno=fd;
    f->flag=flag;
    f->flush_method=LINE_FLUSH;
    memset(f->outbuffer,0,sizeof(f->outbuffer));
    return f;
}

MyFile *MyFopen(const char *path,const char *mode)
{
    int fd=-1;
    int flag=0;
    if(strcmp(mode,"w")==0)
    {
        flag=O_CREAT|O_WRONLY|O_TRUNC;
        fd=open(path,flag,0666);
    }
    else if(strcmp(mode,"a")==0)
    {
        flag=O_CREAT|O_WRONLY|O_APPEND;
        fd=open(path,flag,0666);
    }
    else if(strcmp(mode,"a")==0)
    {
        flag=O_RDWR;
        fd=open(path,flag);
    }
    else
    {
        //TODO
    }
    if(fd<0) return NULL;
    return BuyFile(fd,flag);
}

void MyFclose(MyFile *file)
{
    if(file->fileno<0)return;
    MyFFlush(file);
    close(file->fileno);
    free(file);
}

int MyFwrite(MyFile*file,void *str,int len)
{
    //1.拷贝
    memcpy(file->outbuffer+file->bufferlen,str,len);
    file->bufferlen+=len;
    //2.判断是否满足刷新条件要不要刷新到内核
    if((file->flush_method&&LINE_FLUSH)&&file->outbuffer[file->bufferlen-1]=='\n')
    MyFFlush(file);

    return 0;
}

void MyFFlush(MyFile *file)
{
    if(file->bufferlen<=0)return ;
    //刷新到内核
    int n=write(file->fileno,file->outbuffer,file->bufferlen);
    //刷新到磁盘中
    fsync(file->fileno);
    file->bufferlen=0;
}
